EXPANDABLE AND DRILLABLE LANDING SEAT

摘要

An expandable ball seat (100) comprises a main part (110) made of a first material, and comprising an inner cylindrical surface (111) and a plurality of seat members (120) configured to form a landing seat (121) for a drop ball in an initial position and are radially movable to a final position in which the drop ball can pass between them. Each seat member (120) comprises a drillable part made of a second material that is less hard and less tensile than the first material. Only the drillable part is allowed to extend radially further inward than the cylindrical surface (111) in the final position.